Scorpions' fluorescence under ultraviolet (UV) light may help them to detect and avoid the light. Because night-time levels of UV light correlate with the Moon phase, this could enable the creatures to detect moonlight and remain obscured on moonlit nights.
Carl Kloock and his team at California State University in Bakersfield reduced the glow of 15 female Paruroctonus becki scorpions (pictured) by exposing them to 16 hours of low-level UV light per day. The authors placed the creatures, along with 15 control, fluorescing scorpions, in Petri dishes that were painted black across one half. The scorpions were then exposed to infrared (IR) light only, IR and UV, or IR and white light.
The team found that, when exposed to UV light, the fluorescent scorpions were less active than the reduced-fluorescent ones, moving less often between the light and dark parts of the Petri dishes.